Instrument pointer



June 6, 1933; E. G. HAVEN iNS'IRUMENT POINTER Filed Sept. 23, 1932 Inventor-z Edwavd G Haven, MW v i a,

His Attorney.

Patented June 6, 1933 v I i i I l I UNITEDLSTATES PATENT OFFICE EDWARD G; HAVEN, F so0TIA,;NEW YORK, AssIGNoR T0 GENERAL EL ECTnIC COMPANY, A CORBORATION OF NEW YORK I INsrnn-Mmwr foiNTrtR V if I Application filed September 251m. Serial No. 634,545.;

I My invention relates to indicating instruthe following description to the accomments and pointers therefor. Its principal panying drawing in which 1 represents object is to provide 'POlIllZBIS or increased lnperspectlve the moving elementofan ini strength and rigidity and'diminished tenddic'ating instrument with an indicating I pointer assembled thereon in accordance 55 Another object ofijmy. inventionris to prowith my invention; Fig. 2 is a plan ,view of vide a pointer'for which'there will be no fre-. the pointer; F 3 is an elevation of the quency within the range of frequencies of po1nter;F1gs.4 and 5are views of cross secr vibration to'which" aircraft instruments are t ons takenattwo points indicated in Fig. 3; l0 subjected, at which the amplitude of vibraandlfig 6 is a .view partially in cross sec 60 tionisgreater than at; any other frequency, tlo uindlcating the manner of securing the and for which'the amplitude of vibration at P 1 1 o the. cross arm of the movable elean frequencies is relatively very small. n entof the instrument. I I

Itis a further object of my invention'to will be understood that my inventionis produce a pointer for indicating instruments applicable to any type of instrument having 65 having a construction which provides suflia moving elementrequiring anlindicating cient strength and rigidity to permit carrypointer, but for the sake of setting forth more ing a relatively thick coating of luminous Clearly the nature ofmy invention I haveil+ paint. Still another object of my invention lustrated and described my invention in conis to provide an indicating pointer and a nection with the moving element of an elec- 7 method of attaching to indicating instrutrlcal instrument having a movable coil .11' ments which will permit the use of such incarried by a'shaft 12. The shaft 12 also carstruments on board aircraft and in' other i'lesa crossiar1n13 to which thepointer 14v g applications in which the instruments are is attached. The end of the pointer secured subjected to severe vibrationsL- Other and to the cIfOSS rm. 13 is p ra ly ubSta-II 75 further objects will become apparent as the tially circularinsection, but from the point description proceeds. Y 15 to the tip 16 shownin Fig.2, the pointer a In accordance with my invention in its 13 graduallyflattened. Care is takenthat preferred formylutilizea length of seamless there shall be no abrupt changes inthesha e I 7 tubin'g'to form the pointer for an indicating of the cross section at any point alongt e 80 instrument. One end of the tubing is slipped pointer in order that there will be no weak I over the cross arm of the movingelement of point and also in order that the material vof the indicating instrumentand is secured to Which-the pointer is composed will be unithe cross arm by forming-a bend in the cross formly strained along theportion which is arm and. the portion of the-tubing Where they gradually flattened. The tip 16 is complete- 85 overlap. The indicating tip of the pointer ly flattened andpreferably trimmed to a r is formed by flattening the tip and trimming point to form, an index which may cooperate the tip to a point. Careistakento cause the with a scale, not shown, a r

: pointer to be flattened gradually from anin- Figs. 4 and. 5 illustrate the cross sections 40 termediate point to-the' indicating tip in cut by planes 4 and 5indicated in Fig. 3. 90 order that there will be no weak point bewill be observed that at plane 4 where there tween the normal tubular section and the is relatively greater-bending stressthan at flattened portion in order that thematerial the end of the pointer, the pointer has relawill be substantially] uniformly strained tively great depth, whereas at the plane 5 throughout the length-of the flattened porwhere there is negligible bending stress the 95 tion. The features of my invention which pointer is almost completely flattened so'as Ibelieve to'be novel and patentable will be to have relatively little depth compared with pointed out in the claims appended hereto. its width. As is well known, the section of In order to aflorda more complete undergreater depth has greater strengthwith re- 1 standing of my invention, reference is made spect to bending stress and consequently the 1 0 it 5 ency to vibrate.

strength and rigidity of the pointer are increased by this construction. The increased rigidity provided by my construction also diminishes the tendency to vibrate. Obviously greater strength and rigidity are obtained than could be obtained from pointers punched from flat sheets.

In the case of instruments used on air craft, for instance, on which the apparatus is subjected to severe vibrations which may vary in frequency up to approximately 2000 vibrations per minute, it is essential that the instrument pointers have substantially no tendency to be forced into vibration by vi brations of any frequency to which the apparatus may be subjected. As a result of the strength provided by my construction I am able to apply a relatively thick coating 17 of luminous paint, for example, without causing the pointer to be broken by the stresses which would be set up by vibration. The flattened surface also presents a relatively large area to view in the plane of its move- 'ment, making the pointer easily visible.

Referring to Fig. 6, the pointer is preferably attached to the cross arm 13 by swaging the cross arm to fit the inside of the pointer and bending the two by means of a special tool to produce the conformation shown. Preferably, the joint is cemented in order to further insure the absence of relative motion between the two parts and to increase rigidity. Preferably, the edges 19 of the tip of the pointer are sealed in order to reduce any tendency that there might be for the surfaces to separate and in order to increase further the rigidity of the pointer.

" In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

' What I claim as new and desire to secure by Letters Patent of the United States is:

' 1. In combination with an indicating instrument having a movable element, a pointer therefor comprising a length of seamless circular tubing having one end attached to said movable element and the other end flattened in the plane of its movement and trimmed to a V-shaped tip to form an index, said tip being sealed to provide additional rigidity and said flattened portion being tapered gradually from a circular section to a fully flattened section with two sides in contact, thereby preventing the existence of a weak I point between the flattened section and the circular section and causing the material along the length of the flattened portion to be strained uniformly.

2. 'In combination with an indicating instrument having a movable element, a cross arm attached to said movable element, and a pointer comprising a length of tubing having one end surrounding and secured to said cross arm and the other end flattened in the plane of its movement and trimmed to form a flat pointed tip, said pointer being gradually flattened from an intermediate portion to said tip so as to avoid any abrupt change in .shape of the cross section, thereby preventing the existence of a weak point anywhere along said pointer and causing the material along the length of the gradually flattened portion to be strained uniformly.

8. In combination with an indicating instrument having a movable element, a cross arm attached to said movable element, and a pointer comprising a length of tubing having one end surrounding saidcross arm and rigidly fastened thereto by forming a bend in the cross arm and the tubing together, in

the portion where they overlap.

4. A pointer for an indicating instrument comprising a length of tubing having one end flattened and trimmed to form a flat pointed tip, said tubing being gradually flattened from an intermediate portion to said tip so as to avoid any abrupt change in shape of the cross section, thereby preventing the existence of a weak point anywhere along said pointer and causing the material along the length of the gradually flattened portion to be strained uniformly.

5. A pointer for an indicating instrument 1 comprising a length of tubing having one end flattened and trimmed to form a flat pointed tip, the edges of the material forming said tip being sealed together in. order to provide additional rigidity, said tubing being gradually flattened from an intermediate portion to said tip so as to avoid any abrupt change in shape of the cross section, thereby preventing the existence of a weak point anywhere along said pointer and causing the material along the length of the gradually flattened portion to be strained uniformly.

6. A pointer for an indicating instrument comprising a length of tubing having one end flattened and trimmed to form a flat pointed tip, said pointer being coated on one side with luminous paint, said tubing being gradually flattened from an intermediate portion to said tip so as to avoid any abrupt change in shape of the cross section, thereby preventing the existence of a weak point anywhere pointed tip, the edges of the material forming said tip being sealed together in order to provide additional rigidity, said pointer being coated on one side with luminous paint,;said tubing being gradually flattened from an intermediate portion to said tip so as to avoid any abrupt change in shape of the cross section, thereby preventing the existence of-a.

weak point anywhere along said pointer and causing the material along the length of the gradually flattened portion to be strained uniformly, thereby providing sufficient strength to permit applying a relatively thick coating of luminous paint.

In witness whereof, I have hereunto set my hand.

EDWARD v G. HAVEN. 

